Method for the immobilization of cationic active ingredients on surfaces

Abstract

A method and composition for immobilizing an antimicrobial active ingredient on a surface of a substrate, in which the surface of the substrate is treated with a composition comprising

• • (i) a solvent,
  • (ii) a hydrophobin,
  • (iii) a cationic antimicrobial active ingredient,
  • (iv) optionally additives or auxiliary components,

which permits a long-lasting antimicrobial finishing of the substrate surface.

Description

RELATED APPLICATIONS[0001]This application claims benefit of U.S. provisional application 61 / 392,501, filed Oct. 13, 2010, which herein is incorporated by reference in its entirety.SEQUENCE LISTING[0002]The Sequence Listing associated with this application is filed in electronic format via EFS-Web and is incorporated by reference into the specification. The name of the text file containing the Sequence Listing is SEQUENCE_LISTING—13156-00443-US_ST25.txt. The size of the text file is 73 KB, and the text file was created on Oct. 13, 2011.BACKGROUND OF THE INVENTION[0003]Antimicrobial finishing of surfaces and the application of antimicrobial active ingredients to various substrates (“depositioning”) are of great practical importance for a variety of technical applications. In medical technology and in many sectors of domestic and clinical hygiene, the long-lasting avoidance of a bacteria colonization plays a decisive role.[0004]One aim when applying antimicrobial active ingredients is...

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Benefits of technology

[0266]The effect of the antimicrobial finishing of the investigated surfaces was determined by means of a statistical biofilm assay. For this, the surfaces to be tested were cut into round disks which fit into the holes of 24-well microtiter plates. In order to prevent the surfaces from slipping during the assay, the surfaces were immobilized on the bottom of the microtiter plates with the help of glass joint grease.

[0267]The formation of biofilms was carried out starting from a preculture. For this, 20 ml of the standard commercial TSBY medium (Difco Laboratories, MI, USA) were inoculated with the help of a steady-state overnight culture of Staphylococcus epidermidis DSM1798, Escherichia coli DSM 5698, Proteus mirabilis DSM 4479 or Escherichia coli BL21 (DE3) with an optical density of 0.1. The preculture was incubated for 2 to 4 hours with agitation (at 200 rpm) and 37° C. until an optical density of from 2 to 3 was reached. In order to start the biofilm assay, the preculture was diluted to an optical density of 0.0004 in 5% TSBY in saline (0.9% NaCl) (ca. 105 cfu/ml). 1 ml of this was placed onto the surfaces in the 24-well plate and then incubated at 37° C. with gentle vibration at 50 rpm (revolutions per minute), so that a biofilm could form on the surface.

[0268]The biofilm on the surfaces was analyzed after one hour (1 h) and after 24 hours (24 h) (and optionally 5 hours). For this, the planktonic cells were removed. The surfaces were then removed from the microtiter plate and briefly washed in sodium chloride solution, saline (0.9% NaCl). The adherent cells in the biofilm were then detached from the surface by means of an ultrasound treatment. For this purpose, the surfaces were tran

Problems solved by technology

All of these additional steps are associated with high complexity and costs.

Further prior art problems are the deactivation of the cationic antimicrobial active ingredients as a

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